Plasma homocysteine, methylenetetrahydrofolate reductase mutation and carotid damage in elderly healthy women.

Plasma homocysteine (Hcy) is an independent vascular risk factor. Its remethylation to methionine is regulated by the activity of the enzyme 5,10-methylene tetrahydrofolate reductase (MTHFR). A C-to-T substitution at nucleotide 677 of the MTHFR gene is frequently associated to hyperhomocysteinemia. In this study, we evaluated the relationship among MTHFR C677T polymorphism, Hcy and some ultrasonographic parameters at the level of carotid arteries in 120 elderly women with normal ECG, normal blood pressure values, total cholesterol <250 mg/dl, normal glucose tolerance, normal albumin excretion rate. In all subjects, we measured Hcy by HPLC, MTHFR mutation by polymerase chain reaction followed by HinfI digestion and intima-media thickness (IMT), peak velocity of the systolic flow (SP(V)), end-diastolic velocity (ED(V)) and resistance and pulsatility indexes of intracranial circulation (RI and PI) by ultrasound imaging. Twenty-eight women were homozygotes for the wild type allele (Ala/Ala), 72 were heterozygotes (Ala/Val) and 20 were homozygotes for the mutation (Val/Val). Groups were comparable for age, blood pressure values and plasma lipid levels. Hcy was higher in Val/Val group; moreover, after adjustment for confounding factors, Val/Val had significantly greater IMT and ED(V) (P<0.001 and P<0.05, respectively). Logistic analysis revealed that Val/Val genotype was the strongest risk factor for IMT (OR 30.8, 95% CI 2.82-335.6). Our results show that, in elderly healthy women, Val/Val homozygosity for C677T mutation in MTHFR gene could identify subjects at risk for asymptomatic carotid atherosclerotic impairment.